Studied with Schoenberg
and at Vienna Conservatory. Hungarian regiment in World War I and wrote Gegen den Krieg (Against War) in the following year. Conducted workers choirs, proofreader at Universal Edition. Collaborated with Bertold Brecht
and worked with agitprop groups. In 1933 escaped from Germany (trailed by Gestapo). In 1935 lectured in US, became President of the International Music Bureau. In 1937 returned to Spain, Paris, Denmark and Prague, worked with Ernst Bloch
on political art, composed Lenin Requiem. In 1938 moved to USA, taught at New School for Social Research, composed 12-tone string quartet. In 1942, moved to Hollywood. Writes Composing for the Films with T. Adorno
. Expelled by HUAC from USA in 1948. In 1949 composes national anthem for the GDR. Professor at the Musikhochschule in Berlin. In 1956 composes filmscore for Alain Resnais Nuit et brouilliard (Night and Fog). President of the Music Advisory Committee of the GDR.